As the Democratic convention has finished up and the Republican one is getting ready to go, politics are on the mind of a lot of people. Are you one of them, or are you the type who couldn’t care less? Turns out that your genes could help decide if you plaster your car with political bumper stickers or don’t bother to turn out to vote.

So do my genes decide who I vote for?
Though there is some evidence that there is a genetic basis for personality traits that might affect your opinions on political issues, a recent study looks instead at the strength of your political convictions, regardless of what opinions those may entail. This study suggests that there is actually a link between your genes and how strongly you feel about politics. So you’re more likely to have strong political opinions if your relatives do.

How can scientists know that this comes from your genes and not your environment?
This is, of course, the old nature-nurture question. For many years, people have tried to investigate which traits are determined by your genes, which are determined by the world around you and which are a product of both.

It’s true that if you were raised in a house where your parents were very politically active, you might be more aware of and involved in politics, and in the opposite kind of environment, you might be more likely to be apathetic. This is a very important confounding factor in these kinds of studies and scientists try to get to the root of these issues in many different ways. In this case, they chose to do a twin study.

What does studying twins tell us about genetics?
It’s very difficult to address the nature-nurture phenomenon in a scientific way in human beings, because it’s unethical to manipulate either the nature (genes) or nurture (home, upbringing, etc.) components of a person. Instead, scientists are limited to observing people without interfering. Using twins for these observations is a trick that helps them to start to separate each of these factors.

There are two kinds of twins: identical and fraternal. Identical twins have 100% of the same genes, while fraternal twins share 50%, on average. Scientists observe these different kind of twins and can record information about all sorts of things, such as medical conditions, personality traits or psychological characteristics. They choose pairs of twins that were raised in the same household and therefore have very similar environments. That way, they can attribute differences that they see between the two groups to genetics.

How exactly does this work?
In this study, for example, scientists found that identical twins were more likely to be similar in the strength of their political opinions than fraternal twins were. Since the twin study helps to eliminate environmental effects, this means that genes do contribute to the strength of someone’s political convictions.

However, environment clearly also plays a role! From two different studies, scientists estimate that political conviction is about 50-75% influenced by genetics, which means that the rest is determined by your environment.

So do scientists know what gene is responsible?
No, even though they have shown there is a genetic component, they don’t really know what that might be. Many traits, like height, weight and intelligence are influenced by a number of different genes, and it is possible that is the case here as well. In order to identify what gene or genes are responsible, scientists would have to go through a complex process called mapping and to do that, they would have to know a lot more about the genome sequence of each of the twins in their study. So for the foreseeable future, scientists won’t have any idea what kind of genes might be responsible for determining whether you’re reading CNN.com or Perez Hilton (or both) this November.

THE BOTTOM LINE
Genes play a role in defining many of your traits, including in determining the strength of your political convictions. However, genes do not play the only role – your environment also plays an important part in deciding how much you care about politics.